#include    <stdio.h>
#include    <string.h>
#include    <sys/types.h>
#include    <dirent.h>
#include    <sys/stat.h>

void do_ls(char[]);
void dostat(char *);
void show_file_info( char *, struct stat *);
void mode_to_letters( int , char [] );
char *uid_to_name( uid_t );
char *gid_to_name( gid_t );

int main(int argc, char *argv[])
{
if ( argc == 1 )
    do_ls( "." );
else
    while ( --argc ){
        printf("%s:\n", *++argv );
        do_ls( *argv );
    }

return 0;
}

void do_ls( char dirname[] )
{
DIR     *dir_ptr;       
struct dirent   *direntp;       

if ( ( dir_ptr = opendir( dirname ) ) == NULL )
    fprintf(stderr,"ls1: cannot open %s\n", dirname);
else
{
    while ( ( direntp = readdir( dir_ptr ) ) != NULL )
        dostat( direntp->d_name );
    closedir(dir_ptr);
}
}

void dostat( char *filename )
{
struct stat info;

if ( stat(filename, &info) == -1 )      
    perror( filename );         
else                    
    show_file_info( filename, &info );
}

void show_file_info( char *filename, struct stat *info_p )
{
char    *uid_to_name(), *ctime(), *gid_to_name(), *filemode();
void    mode_to_letters();
    char    modestr[11];

mode_to_letters( info_p->st_mode, modestr );

printf( "%s"    , modestr );
printf( "%4d "  , (int) info_p->st_nlink);  
printf( "%-8s " , uid_to_name(info_p->st_uid) );
printf( "%-8s " , gid_to_name(info_p->st_gid) );
printf( "%8ld " , (long)info_p->st_size);
printf( "%.12s ", 4+ctime(&info_p->st_mtime));
printf( "%s\n"  , filename );

}

void mode_to_letters( int mode, char str[] )
{
strcpy( str, "----------" );           

if ( S_ISDIR(mode) )  str[0] = 'd';    
if ( S_ISCHR(mode) )  str[0] = 'c';    
if ( S_ISBLK(mode) )  str[0] = 'b';    

if ( mode & S_IRUSR ) str[1] = 'r';    
if ( mode & S_IWUSR ) str[2] = 'w';
if ( mode & S_IXUSR ) str[3] = 'x';

if ( mode & S_IRGRP ) str[4] = 'r';    
if ( mode & S_IWGRP ) str[5] = 'w';
if ( mode & S_IXGRP ) str[6] = 'x';

if ( mode & S_IROTH ) str[7] = 'r';    
if ( mode & S_IWOTH ) str[8] = 'w';
if ( mode & S_IXOTH ) str[9] = 'x';
}

#include    <pwd.h>

char *uid_to_name( uid_t uid )
{
struct  passwd *getpwuid(), *pw_ptr;
static  char numstr[10];

if ( ( pw_ptr = getpwuid( uid ) ) == NULL ){
    sprintf(numstr,"%d", uid);
    return numstr;
}
else
    return pw_ptr->pw_name ;
}

#include    <grp.h>

char *gid_to_name( gid_t gid )
{
struct group *getgrgid(), *grp_ptr;
static  char numstr[10];

if ( ( grp_ptr = getgrgid(gid) ) == NULL ){
    sprintf(numstr,"%d", gid);
    return numstr;
}
else
    return grp_ptr->gr_name;
}

